The present invention relates generally to passenger conveyors and, more particularly, to systems for detecting a person's position relative to the passenger conveyor.
Passenger conveyors, such as escalators and moving walkways, are used to efficiently convey passengers from a first location to a second location. A typical escalator comprises a plurality of moving steps that are linked together and attached to chains that travel over a pair of sprockets at each end of the escalator, one of which is driven by a machine. A balustrade flanks each side of the moving steps, and each balustrade includes a moving handrail that moves simultaneously with the steps. A typical moving walkway contains many of the same components as the escalator, except that the walkway is substantially flat rather than inclined and uses pallets instead of steps.
Passenger sensing systems have been used to either cease or trigger operation of the passenger conveyor for safety reasons, maintenance reasons, or energy-cost savings. Typically these passenger sensing systems have used multiple sensors at the entrance and exit gates or along the length of the passenger conveyor in order to detect whether there is a person approaching the entrance and exit gates or riding on the passenger conveyor. These sensors have been optical sensors, infrared sensors, piezoelectric sensors, or RF transmitters. Because the number of sensors required increases as the length of the passenger conveyor increases, these systems can be prohibitively expensive to install and maintain.